These are the two kaiju brothers that was in their own godzilla movie and based on the mountain and ocean environment. Their colors separates them from each other with sanda being a tan/brownish color and gaira of blue/greenish color.

Classification: Frankenstein spawn

Powers and Abilities: Superhuman physical characteristic, immortality(type 1 and 3), stealth mastery, large size(type 1), enhanced senses, natural weaponry(teeth), regeneration(High-Low), skilled in hand to hand combat.

Attack potency: Building level(Sanda can crush buildings under his weight using his limbs)

Speed: At least Superhuman travel speed, reaction and combat speed

Lifting Strength: Class M by sheer size

Striking Strength: Building Class

Durability: Building level(Took beatings from gaira), regeneration makes him hard to kill due to being spawned by Frankenstein immortal cells.

Stamina: Extremely high

Range: Tens of meters by sheer size

Standard equipment: Teeth

Intelligence: Average

Weakness: In the war of the gargantuars, Gaira has a strong aversion to sunlight, and will retreat whenever the sun rises.

Gaira

Classification: Frankenstein spawn

Powers and Abilities: superhuman physical characteristic, stealth mastery, immortality(types 1 and 3), enhanced senses, all previously abilities stated before. 

Attack potency: Building level(Gaira fought on par with Sanda)

Speed: At least Superhuman travel, reaction and combat speed

Lifting Strength: Class M due to sheer size

Striking Strength: Building class

Durability: Building level(Took beating's from Sanda), regeneration makes him hard to kill due to being spawned from Frankenstein immortal cells.

Stamina: Extremely high

Range: Tens of meters due to sheer size

Standard equipment: teeth

Intelligence: Below average

Weakness: In the war of the Gargantuas, Gaira has a strong aversion to sunlight, and will retreat whenever the sun rises.